Trojan Boat Forum

I have what seems to be a prop shake after just getting a new prop from Michigan wheel. The shake does not start until above 3500rpms when the boat is loaded and I'm at about 11 to 12 mph. There is no cupping on the prop, the drive shaft and couplings are new, then engine has been swapped for a crusader 454. All run smooth as a lathe. I had the wrong prop before and was getting a shake at all rpm's. Suggestions?

You should be running faster then 11-12 at 3500 bottom clean? What size prop are you running ? and what gear ratio ? Is it a velvet drive trans ? If so is the prop the proper direction and the trans in the true forward position ?( lever forward ) , I have run it to it several times with engine and prop swaps .

It's a 14 x 10 lh 1 inch shaft prop I'll look to see what the gear ratio is but I assumed it was stock. The bottom is clean no issues issues there. Forward is lever forward. I'll be out at the boat this weekend anything else I should check. Engine and drive shaft seem smooth.

Engine could be missing too

Engine is smooth no miss from it at all, I am a service manager at a dealership. I'm great with cars, engines and stuff, boat stuff I don't have a lot of experience though

Check shaft alignment not much room for error . .Check the cutlass bearing. Make sure the prop is seated and not riding up on the key . Did you lap it in ? look at he engine mounts make sure they look to "crushed" about they same ( carrying about the same weight ) . Make sure the exhaust has some flex and not grounding out . Make sure the engine is not missing under load ( it can be harder to tell in a boat then a car )

Are the struts solid? Any flex in the hull bottom where the struts are bolted on?